G.O.P. Is Making Progress Toward Presidency but Is Still Playing Catch-Up

After five of six presidential elections in which the Republicans have lost the popular vote, this year’s midterm elections point toward a plausible Republican path to winning the White House.

The Democratic losses were not simply because of low turnout. Republicans often made significant gains among rural, white voters. Some candidates made inroads among young and Hispanic voters, as well, according to exit polls and county and precinct-level results.

But the Republican path is also narrow, one the Democrats could block if they reassemble their support among the young, nonwhite and suburban voters whom President Obama won in 2008 and 2012. In the simplest of terms, Republicans made progress this year toward solving their demographic problems, but not enough. “It was an excellent election night,” said Glen Bolger, a Republican pollster, “but it doesn’t solve our problem in demographics in presidential years.”

The results in Iowa were the clearest illustration that the Republican landslide on Tuesday was not just because of low Democratic turnout in off-year elections.

On Tuesday, Joni Ernst, now a Republican senator-elect, won a decisive nine-point victory. She swept much of traditionally Democratic eastern Iowa, where Democrats have long fared well with rural voters.

In Colorado, Cory Gardner, now a senator-elect, also made significant gains among rural white voters. He also outperformed past Republicans in traditionally Democratic, heavily Hispanic counties.

These gains suggest that demographic trends have not doomed Republicans to minority-party status, as some political analysts predicted. Those predictions hinged in part on the assumption that Democrats could fare no worse among white voters than Mr. Obama. That assumption ignored Mr. Obama’s strengths among white voters outside the South.

Whether the coalition that Mr. Obama assembled in 2008 and 2012 can be remobilized in 2016, without Mr. Obama on the ballot, is a big question. But Tuesday contained enough good news for Democrats, obscured by their many defeats, that it would be unwise for Republicans to assume that the coalition cannot be rebuilt.

Democrats would have narrowly won key races in Colorado and North Carolina if the electorate were as young and diverse as it was in 2012, and as Democrats hope it will be in 2016. It could be even more diverse, given the powerful demographic forces underlying the growth of the nonwhite share of the electorate over the last decade. Democrats also maintained most of their support among college-educated whites and black voters, a combination that would make it hard for Republicans to win 2016.

Yet the Republicans still made meaningful gains, enough to turn some states red if they could be replicated in two years. Their main challenge is to find ways to extend those gains over the next two years, and especially to replicate their gains with white voters in 2014 among other groups.

It may seem unlikely that future Republican presidential candidates could do better among white voters than Mitt Romney did against Mr. Obama. The national exit polls showed that Mr. Obama received just 39 percent of the white vote in 2012, the lowest since Walter Mondale in 1984.

Yet Mr. Obama’s weakness was almost entirely attributable to white voters in the South and Appalachia. Outside of those regions, Mr. Obama fared well among white voters. He was a strong candidate among white voters across much of the northern half of the country, easily winning overwhelmingly white states like New Hampshire, Wisconsin, Minnesota and Iowa.

It is not obvious that future Democrats can count on repeating Mr. Obama’s strength among Northern white voters. Not only did Mr. Obama run ahead of past Democrats, he defeated Hillary Rodham Clinton in many of these regions in the 2008 primaries.

The next Republican presidential candidate could outperform Mr. Romney among white voters by holding Republican gains in the South and winning back some of the white Obama voters of the rural North.

Many analysts have assumed that the next Democratic candidate, perhaps Mrs. Clinton, will be able to both maintain the support of these Northern rural voters and outperform Mr. Obama among Southern white voters, perhaps by a significant margin. Yet none of the strong Democratic Senate candidates in the South — Mary L. Landrieu, Alison Lundergan Grimes, Michelle Nunn, Kay Hagan, Mark Pryor and Mark Warner — did significantly better among white voters than Mr. Obama.

This pattern deals a blow to Democratic hopes of competing in Georgia in 2016, a state they had hoped would follow Virginia’s and North Carolina’s path and become a swing state.

But if Iowa gives Republicans their biggest reason for hope, Colorado and North Carolina offer reasons for caution, even though Republicans won Senate seats in both. In those two states, the Republican victories appeared to rely on low turnout, and Democrats fared very well among college-educated white voters. In Colorado, Senator Mark Udall, a Democrat, lost by two points in a state that Mr. Obama won by five points. But Mr. Udall ran what was widely considered to be a mediocre campaign, focused relentlessly on Mr. Gardner’s past support for a “personhood” amendment that would confer constitutional rights at conception.

Had young voters and registered Democrats turned out at the rates they did in 2012, Mr. Udall would likely be looking forward to another term, according to an Upshot analysis of voter file data from the Colorado secretary of state.

Mr. Udall maintained nearly all of Mr. Obama’s support among college-educated white voters. He even outperformed Mr. Obama among college-educated white voters, according to exit polls. Jefferson County, a suburban county consisting mainly of well-educated white voters west of Denver, and a bellwether in statewide elections, went to Mr. Udall, narrowly.

The story was similar in North Carolina, where Ms. Hagan also ran ahead of Mr. Obama among college-educated white voters, according to the exit polls. Ms. Hagan posted a better showing in Orange County, which includes Chapel Hill, and in Durham than any Democratic presidential candidate since Franklin D. Roosevelt, winning 75 percent of the vote.

The Republicans could fail to capitalize on the opportunities presented by Mr. Obama’s unpopularity; some are already interpreting the lower nonwhite and youth turnout rates of 2014 as evidence that Democrats cannot mobilize nonwhite voters without Mr. Obama on the ballot. However, there is a tendency for nonwhite and young voters to turn out at lower rates in midterm elections than in presidential elections.

Last week’s results suggest that Republicans would be taking a big risk if they count on nonwhite turnout falling so low again. The vaunted Democratic mobilization effort did not replicate the 2012 electorate — something it could never do given the tendency for nonwhite and young voters to stay home — but it did produce a notably more Democratic electorate in states like North Carolina and Colorado than in 2010.

The effectiveness of the Democratic turnout effort is perhaps best illustrated by contrasting those states with Virginia, where Mr. Warner nearly lost a state where he was thought to be safe. Democrats did not invest heavily in field operations in Virginia, and turnout was far lower than the other battlegrounds, particularly in the most Democratic precincts and jurisdictions.

There is no way to be sure that the Democrats will remobilize young and nonwhite voters in 2016, even if it is the outcome most consistent with the available data on turnout and demographics. But if they do, the Republicans may need to perform still better in 2016 than they did last week.

The Upshot: The Republican landslide victory
last week was not simply because
of low Democratic turnout in an
off-year election.

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A version of this article appears in print on , on Page A1 of the New York edition with the headline: G.O.P.’s Path to Presidency, Tight but Real. Order Reprints | Today’s Paper | Subscribe